Proteoglycans are being isolated from bovine trachea and bronchi and are being compared with well characterized proteoglycan specimens from bovine nasal septum using physical and chemical analyses. Diced bovine tracheal and bronchial cartilage is extracted with 4M guanadine hydrochloride solution containing protease inhibitors, and the proteoglycans are then separated in cesium chloride density grandients in the ultracentrifuge. Quasi elastic light scattering is then used to determine the translational diffusion coefficients of the extracted proteoglycans; sedimentation coefficents are determined using the analytical ultracentrifuge, and intrinsic viscosities are also measured. These data are being used to determine the molecular size of the lung and tracheal proteoglycans and to compare them with each other, and with the equivalent data for bovine septum proteoglycans. Initial results indicate that bronchial cartilage proteoglycans are more difficult to extract than those from tracheal cartilage and may also be of lower molecular weights. The bronchial proteoglycans are being investigated to see if the same type of aggregate-subunit structure is present as has been found in other cartilages. In the present grant period these studies are being extended to other lung tissues and to human materials.